SPECT has been identified as a possible means for localization of seizure foci in epileptic patients. Recent studies (See, e.g. Rowe et al. "Visual and Quantitative Analysis of Interictal SPECT with Technetium-99 m-HMPAO in Temporal Lobe Epilepsy", Journal of Nuclear Medicine 1991, 32:1688-1694.) have suggested that the time delay between seizure onset and radionuclide injection is a critical factor in determining both specificity and accuracy of the SPECT study. While an interictal SPECT is relatively easy to conduct when compared with an ictal SPECT, the former is found to be less accurate for localizing the ictal focus. However, a problem preventing a more widespread use of the ictal SPECT is that the duration of the post-ictal interval during which the injection of HMPAO-Tc.sup.99 reveals hyperactivity is only about five minutes. Accurate localization of the focus is the most important step in surgical treatment of epilepsy, and must become part of the standard pre-operative patient evaluation. However, there are four obstacles which prevent the use of such a technique. First, the limitation in time between the seizure onset and radionuclide injection must be strictly observed. Second, quality control issues must be addressed and the handling of the radionuclide must be performed by qualified nuclear medicine personnel. Third, radiation safety guidelines must be observed since the radionuclide must be kept at the patient's bedside until a seizure occurs. Fourth, a technique must be readily incorporated into the standard hospital operating environment to avoid extensive training requirements.
In order to achieve the goals of an accurate SPECT technique without a specialized system, a nuclear medicine technologist would need to be at the patient's bedside at all times awaiting the occurrence of a seizure. This technologist would have to be trained in recognition of the onset of the seizure since the medication must be injected within four to five minutes of the seizure. If the injection occurs too soon or too late, the seizure focus may not be visualized.